1. Field of the Invention
The present application is directed to homopolymers prepared from ammonium quaternary salts of amino alkylacrylamides, the processes for preparing same, formulations containing these homopolymers and the use thereof in personal care formulations.
2. Description of the Prior Art
Polyquaternary polymers have been used in a variety of industrial formulations, including cosmetic formulations. However, to date, one of the most important applications is their use in hair and skin formulations, including hair shampoos and hair conditioning products. More specifically, they have been used to sufficiently condition the hair so that it holds a preset configuration.
Hair shampoos generally are formulated with highly effective synthetic surfactants, such as anionic surfactants, that clean the hair. The anionic surfactants not only remove the dirt and soil from the hair but concomitant therewith, they unfortunately also remove all of the sebum naturally present on the surface of hair fibers. As a result, shampoo compositions containing these surfactants leave the hair with an undesirable harsh, dull and dry touch or feel, usually called "creak", after the hair is shampooed and then rinsed with water.
Furthermore, thoroughly cleansed hair also is extremely difficult to comb, in either the wet or the dry state, because the individual hair fibers tend to snarl, kink and interlock with each other. If the hair is incompletely dried, such as hair dried with a towel, the hair has poor brushing properties, and after complete drying, the hair does not set well. The combing or brushing property of the hair remains poor and in low humidity atmospheres, the hair has undesirable electrostatic properties, causing the hair to "fly away", thereby reducing the brushing properties of the hair. The unsatisfactory combing or brushing property of hair immediately after shampooing also causes hair damage, such as split ends or hair breakage. In addition, shampooing of hair reduces the natural luster and resiliency of the hair, thereby giving the hair a dull appearance.
Thus, shampoos usually neither aid in the detangling of wet hair nor impart any residual conditioning benefits to dry hair, such as manageability or styleability of hair sets. The overall unsatisfactory condition of the shampooed hair necessitates the use of a conditioning composition to improve these undesirable physical characteristics. The conditioning composition may be applied separately from the hair shampoo as a post-shampoo treatment of the hair or may be incorporated into the hair shampoo. However, because many of the most widely used products for treating hair contain anionic surfactants and as explained hereinbelow, conditioning compositions usually contain cationic polymers as the active ingredient, and because cationic material are usually inactivated by reaction with anionic surfactants, it is customary to employ conditioner containing cationic materials as a separate composition, such as post-shampoo rinse, separately applied.
The conditioning agents that have been utilized in the prior art are cationic compounds such as cationic surfactants and cationic polymers. They render the hair more manageable. For example, the wet combing problem discussed hereinabove is solved by the use of these conditioners which coat the hair shaft and cause the individual hair shafts in a tress to resist tangling and matting because of the conditioner residue retained on the shaft. The ability of these cationic compounds to absorb or react with the keratinous material of the hair makes them the most desirable compounds for imparting the desired improvement in wet hair detangling and dry hair manageability. Many of these cationic compounds are polyquarternary polymers prepared from monomers with an ester functionality, for example, acrylate or methacrylate types, as a comonomer.
Although they are useful, these polyquaternary polymers containing esters have several disadvantages associated therewith. For example, they tend to be hydrolytically unstable to the extent that the formulation must avoid conditions conducive to hydrolysis during formulation, such as acidic or basic conditions and higher temperatures such as temperatures greater than about 30.degree. C. Under these conditions, they decompose and catalytically hydrolyze as a result of contact with water, including trace amounts thereof, into the (meth) acrylic acid and the corresponding dialkylalkanolamine, resulting in significant lowering of viscosity and concomitant reduction in beneficial properties.
Moreover, the esters used heretofore lack hydrogen bonding capability with skin protein or hair keratin; consequently the hair substantivity, when applied, is not satisfactory.
Furthermore, commercial formulations used heretofore are indiscriminate in the anion utilized. For example, many hair care products utilize anions derived from organic and inorganic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid, hydrobromic acid, hydroiodic acid, acetic acid, propionic acid, formic acid and the like. In the prior art conditioners, the preferred acid is hydrochloric acid, with the anion being a chloride ion. See, e.g., U.S. Pat. No. 4,973,637. However, the presence of a chloride is undesirable, especially because it is a skin irritant. In addition, many conditioning agents are adapted for use as a spray from a container. However, chlorides have corrosive properties, and over a period of time, results in the corrosion of the spray container.
Another problem associated with conditioners heretofore, especially those that absorb particularly strongly to the hair, is that they reduce the elasticity, body and set of the dried hair.
The need for improved compositions that condition the hair has long been recognized in the art. Therefore, although conditioning compositions for applications to freshly shampooed hair are well known, new and improved conditioning formulations based on cationic compounds are continually sought. These new conditioning compositions must overcome the problems discussed hereinabove. They must also be aesthetically acceptable to consumers, improve the wet combing and dry combing properties of hair, leave the dry hair with satisfactory cosmetic and physical properties, including, in particular, dry combing and feel, less hair coating, manageability, and body. The conditioners sought must be substantive to hair.
The present inventors have found a homogenous and clear cationic polymer which, when formulated into a hair conditioning composition, does not suffer from the disadvantages enumerated hereinabove. The resulting formulation is an excellent hair conditioner which gives the hair body moisture, combability, etc. Such formulations are not corrosive or skin-irritants, but yet are stable to pH changes and impart improved physical and cosmetic properties to the hair.